System of control



Unire spares rarnnr lernten.

,CHARLES C. WHITTFLKER, 0F "il/"ILKNSBURG, PENNSYLVANIA, ASSIGNOR TOWEST- INGHOUSE ELECTRIC t TfIANUFAGTRNG COId-PANY, A CORPDRATIC'N 0FPENN- SYLVANIA.

SYSTEM OF CONTRL.

Application iled June 19, 1917.

To all whom t may concern.'

Bc it known that l, CHARLES C, `WHIT- 'rAnnn, a citizen of the UnitedStates, and a resident of llilkinsburg, in thecounty of Allegheny andState of Pennsylvania, have invented a new and useful Improvement inSystems of Control, of which the following is a specilication.

My invention relates to systems of control and especially to theautomatic regu` lation thereof under conditions of slipping or skddingof the associated vehicle wheels in regenerative control systems forlocomotives and the like.

ln the prior art, various schemes have been proposed to eliminateslipping or skidding of dynamo-electric machines during periods ofvehicle propulsion or retardation, such action, in general, beingdependent upon the difference in voltage of the armatures of 'a normallyoperating and a slipping or skidding machine. However, so far as l amaware. no system has been devised for absolutely preventing an immediaterecurrence ofsuch abnormal conditions after they have once beenremedied, and, consequently, it has been possible in such prior artsystems for vsuccessive slipping and rail-gripping to occur until suchtime as the vehicle speed has become materially reduced.v I

lt is the object of my present invention to provide a relatively simpleand effective means for precluding the possibility of an immediaterecurrence of slipping or skidding conditions in the dynamo-electricmachines of a locomotive or the like, whereby such abnormal conditionsare remedied immediately upon their recurrence, and certain machineconditions are so changed that immediate recurrence of slipping orskidding is obviated.

My invention is illustrated in the accompanying drawings, wherein Figure1 is a diagrammatic view of the main circuits of a control systemembodying my present invention; Fig. 2 is a diagrammatic view of certainauxiliaryr circuits for governing the operation of the main machinesthat are shown in F ig. 1; and Fig. 3 is a diagrammatic view of anelectric locomotive unit embodying a plurality of dynamo-electricmachines to which my invention may be applied.l

Referring first to Fig. 3 of the drawings,

Speccation of Letters Patent.

Patented Jan. 13, 1920.

serial No. 175,594.

the structure shown comprises a locomotive cab 1 which. is suitablysupported upon a plurality of articulated trucks 2 and 3 of suitabledesign and which respectively embody a. plurality of sets of drivingwheels 4f and 5 that are adapted to run upon track rails 6, inaccordance with the usual practice. A plurality of dynamo-electricmachines M1 and M2 are provided and may be associated with the wheels ofthe various trucks in any suitable manner, as by driving mechanisms 7and 8 of a familiar type.

Referring now to F ig. 1, the system shown comprises supply-circuitconductors Trolley and Ground; the dynamo-electric machines M1 and M2,which are respectively provided with commutator-type armatures A1 and A2and field windings F1 and F2 of the series type; a plurality ofbalancing resistors R1 and R2 that are associated with the respectivemachine windings in a manner to be set forth; an auxiliary excitingsource for the main field windings, preferably comprising amotor-generator set 10; a variable resistor l1 that is connected in themain-lield-winding circuits and is adapted to be regulated by acontroller 12 having an automatic actuating mechanism 13; a limit switch14 for governing the operation of the mechanism 13, in accordance withcircuit conditions; and a plurality of voltage-relay devices 15 and 16'that are connected across the respective main armatures A1 and A2 for anautomatic governing purpose to be described.

The motor-generator set 10 is shown as comprising a driving or motorarmature 2O that is mechanically associated, in any suitable manner, asby a shaft 2l, with a generator or exciting armature 22. A main orexciting field winding .23 and a compensating )'ield winding 24 areprovided for the driving armature 20, and similar field windings and 26are associated with the generating armature 22.

The controller 12 comprises a movable contact segment 29 that ispreferably mounted upon a drum 30 and is of suitable configuration forsuccessively engaging a plurality of stationary control iingers 31 thatare connected to various points of the fieldwinding-circuit resistor 11,whereby the active circuit value thereof may be varied.

The actuating mechanism 13 is of a fay .miliar electricallyfcontrolled,pneumatically operated type and comprises a pinion 32 mally closed valve39 is likewise provided4 with an inlet pipe or passage l2, and anysuitable source ci fluid pressure (not shown) may be connected to thepipes l-l and 42.

The operation of the electrically-governed apparatus 13, without regardto the circuit connections effected thereby, ma f be `set Jr'orth asfollows: Upon concurrent energizetion of the actuating coils 0n and Off,the initial unbalanced Huid-pressure conditions, whereby then'iechanisin is biased to the illustrated position, are reversed, thatis, luid pressure is admitted to the cylinder' 37 and is released tromthe other cylinder 3S to effect a movement oi' the pistons 35 and 36toward the right. To arrest such movement, at any time, it is merelynecessary to deenergize the Dit coil, whereupon balancedhigh-pressure-iuid conditions immediately obtain in the apparatus, and apositive and reliable stoppage thereof is secured.

To produce a return movement of the controller, the actuating coils Gnand Gil are concurrently denergized, whereby fluidpressure conditions inthe apparatus revertto the original unbalanced state, and the dcsiredbackward movement is eleeted.

Inasmuch as the particular circuit arrangements or inauguratingaccelerating or regenerative operation or the illustrated system areimmaterial to my present invention, which is capable of a wide varietyof applications, l have not deemed it necessary to illustrate ordescribe such arrangements but have eliminated, in so far as possible,main-circuit switches and the like which, it is understood, will benormally employed during the operation of the system.

Assuming, therefore, that the system is operating under regenerativeconditions, for example, the main circuits are established from thetrolley through conductor 50 to junction-point 51, where the circuitdivides, one branch including conductor 52, main armature A1, conductor53 and balancing resistor R1 to a second junction-point 55, and theother branch traversing conductor 5G, main armature A2, conductor 57 andthe balancing resistor R2 to the junction-point 55, whence a commoncircuit is completed neer/,795

'through conductor 58, the actuating coil for the limit switch i4. andconductor 59 to the negative supply-circuit conductor Ground.

The exciting circuit for the main field windings is established from thepositive terminal of the auxiliary generating armature 22 throughconductors 61, 62 and 58 to the junction-point 55, where the circuitdivides, one branch traversing` the balancing resistor R1, main ieldwinding lll and conductor 63 to a junction-point 64e, and the otherbranch including the balancing resister R2 and main lield winding F2 tothe junction-point 64, whence a. common circuit is continued through thevariable auxiliary resistor 11, conductor 66 and compensating fieldwinding 26 to the negative te 1minal oi the generating armature 22.

A further circuit is established from the trolley, through conductor 67,compensating field winding 2l, armature 20 and exciting eld 'winding 23for the auxiliary driving motor, conductor 68, exciting field winding 25for the auxiliary generating armature 22 and thence through conductor 62to ground.

The illustrated maincircuit connections are not of my present invention,but are fully set forth and claimed in a co-pending` application ofRudolf E. Hellmund, Serial No. 44,443. filed August 9, 1915, andassigned to the Westinghouse Electric t lilianulfacturing Company.Consequently, only a brief description or' the operation thereorn will.be necessary to afford a thorough comprehension of the presentinvention.

As indicated by the solid arrows, representing main armature orregenerated current, and the dotted arrows, denoting exciting ormain-field-winding current, both oiC these currents traverse either oneof the balancing resistors lll and R2 in the same direction. Hence, uponan incipient increase of 'regenerated current in the main armature Al,for example, the corresponding voltage drop across the resistor Blimmediately and inherently reduces the portion of the auxiliarygenerating-armature voltage that is available for delivery to the mainfield winding F1, or, in other words, the excitation is variedoppositely to the regenerated current traversing the main armature A1.rlhe converse action occurs 'whenever an incipient decrease ot currentobtains in the main armature. ln this way, a substantially constantregenerated current is maintained in the main arnfiature, irrespectiveof supply-circuit-voltage fluctuations and the like.

To compensate tor the gradual decrease oi? vehicle speed during theretardation period, the excitation or" the main field windings may beincreased by gradually shortcircuiting the variable resistor 11, andthis result is accomplished automatically by the auxiliary system thatis shown in Fig. 2,

comprising the actuatingcoils On and Off for the controller-regulatingmechanism 13, the auxiliary contact members of the relay devices 14, 15and 16, an auxiliary switching device 45 for short-circuiting the.ontact members of the voltage relays 15 and 16 under predeterminedconditions, a master controller MC having a plurality of operativepositions a and Z) for primarily governing the system operation and anauxiliary source of energy, suoli as a battery B.

Upon actuation of the master controller to its initial operativeposition a, a circuit is established from the positive terminal of thebattery B through conductor 69, control fingers and 71, which arebridged by contact segment 72 of the master controller, conductor 73,cooperating stationary and movable contact members 74 and 75 of thevoltage relays 15 and 16, respectively, in their upper or high-voltagepositions, conductors 76 and 77, the actuating coil On and conductor 7 9to the negative terminal of the battery B.

If the master controller is moved to its position b, afurther circuit iscompleted from the contact segment 72 through control finger 80,conductor 81, cooperating stationary and movable contact members S2 ofthe limit switch 14, in its low-current position, and the actuating coilOff to the junction-point 78 and the negative conductor 79.

The forward actuation of the controller 12 to gradually short-circuitthe resistor 11 is automatically governed, in accordance withregenerated current conditions, by the limit switch 14, in conformity toa familiar practice, under normal operating conditions. The lifting ofthe limit switch interrupts the circuit of the off coil and thus arreststhe movement of the controller 12, as

previously explained.

However, in case either of the main armatures A1 and A2 and the sets ofvehicle wheels 4 and 5 that are respectively associated therewith shouldslip or skid, the voltage of that armature is materially reduced, as iswell understood, whereby the corresponding voltage relay 15 or 16 willdrop to its open-circuit posit-ion to denergizo the on actuating coil.At the same time, the regenerated current will be sufficiently high tolift the limit switch 14 to interrupt the energizing circuit for theactuating coil Off. Consequently, since both actuating coils for themechanism 13 are concurrently denergized, a backward movement of thecontroller 12, to reinsert a greater amount of the variable resistor 11in the main-field-winding circuit and thereby weaken the main-machineexcitation, takes place until voltage and speed conditions of the twomain armatures are again equalized, whereupon normal operation of thesystem, as previously described, will be resumed and,

furthermore, `no immediate recurrence of such slipping or skiddingconditions will obtain, by reason of the weakened mainfield-windingexcitation. In this way, 1 provide a control system, wherein slipping orskidding conditions of a dynamo-electric machine are immediatelyremedied, and no further alternate slipping and rail-gripping7 canpossibly obtain until a considerable time interval has elapsed and speedconditions of the vehicle have materially. decreased.

In lieu of varying the resistor 11 tol compensate for the gradualdecrease of vehicle speed, other well-known methods, such as changingthe active circuit value of the resistors R1 and R2, or of resistorsthat are connected in shunt to the exciting field winding 23, may beutilized.

If it is desired to exclude the voltage relays 15 and 16 from activecircuit regulation during the accelerating period, this result may beaccomplished by closing the switching device 45 (Fig. 2), whereby acircuit is completed from the conductor 7 8 through conductor 83,switching device 45 and conductor 84 to the conductor 77, or, in otherwords, the cooperating contact members 74 and. 75 of the voltage relaydevices 16 and 15, respectively, are short-circuited and renderedineffective.

1 do not wish to be restricted to the specific' circuit connections orarrangement of parts herein set forth, as various modifications thereofmay be effected without departing from the spirit and scope of myinvention. I desire, therefore, that only such limitations shall beimposed as are indicated in the appended claims.

T. claim as my invention:

1. 1n a system of control, the combination with av plurality ofdynamo-electric masingle means for simultaneously regulating theoperation thereof, means dependent upon a material departure in thespeed of either machine from normal for actuating said single regulatirmeans to weaken the machine excitation, ufhereby further speeddepartures under the existing opera-ting conditions are prevented.

2. In a system of control, the combination with a `plin'fality ofdynamo-electric machines associated with a common load, of single meansfor siinultaneously regulating the operation thereof, and meansdependent upon the slipping of any machine for actuating said singleregulating means to modify the mach ine excitation, whereby saidslipping7 is remedied and further slipping under the existing generalmachine conditions is obviated.

3. In a .system of vehicle control, the combination with a plurality ofdynamo-electric machines for operating the vehicle along `chinosassociated with a common load, of

track rails, of single means for simultaneously regulating the operationof said machines, and means dependent upon the slipping of any machinefor actuating said single regulating means to weaken the machineexcitation, wherebysaid slipping is remedied by causing thecorresponding machine to grip the rails and successive slipping andrail-gripping is obviated.

el. ln a system of regenerative vehicle control, the combination with aplurality of momentum-driven dynamo-electric machines for operating thevehicle along track rails, of means for separately exciting saidmachines, means for regulating such excitation, and means dependent uponthe slipping of any machine for actuating said regulating means tomodify the machine excitation, whereby said slipping is remedied bycausing the corresponding machine to grip the rails and successiveslipping and railgripping is obviated.

5. In a system of control, the combination with a plurality ofdynamo-electric machines severally having armatures and field windings,of single means for simultaneously varying the excitation of said fieldwindings, and means dependent upon a material departure in the speed ofeither machine from normal for actuating said single varying means toweaken the field excitation, whereby the machine speeds are equalizedand immediate recurrence of said speed departure is prevented.

6. ln a system of control, the combination with a plurality ofdynamo-electric machines severally having armatures and eld windings, ofsingle means for simultaneously varying the excitation of said fieldwindings, and means dependent upon the slipping of any machine foractuating said single varying means to modify the field excitation,whereby said sli]f ping7 is remedied and immediate recurrence thereof isobviated.

7. ln a system of control, the combination with a plurality ofdynamo-electric machines severally having armatures and field windings,of means for separately exciting said field windings, a controller forregulating such excitation, means for operating said controller ineither direction, and means dependent upon a material Voltage differenceof either machine from normal for actuating said operating means toweaken the field excitation, whereby said voltage difference iseliminated and immediate recurrence thereof is prevented.

8. ln a system of control, the combination with a plurality ofdynamo-electric machines severally having armatures and field windings,of means for separately exciting said field windings, a controller forregulating such excitation, an electrically-governed apparatus foroperating said controller in either direction, and means dependent uponthe slipping of any machine for energizing said electrically governedapparatus to modify the field excitation, whereby said slipping isremedied and immediate recurrence thereof is prevented.

9. In a system of control, the combination with a plurality ofdynamo-electric machines severally having armatures and field windings,of means for separately exciting said field windings, a controller forregulating such excitation, an apparatus having a plurality of actuatingcoils for operating said controller in either direction, and a pluralityof relay devices energized from the respective armatures and severallyprovided with contact members that are connected in circuit with one ofsaid coils under predetermined conditions.

l0. ln a system of control, the combination with a plurality ofdynamo-electric machines severally having armatures and field windings,of means for separately exciting said field windings, a controller forregulating such excitation, an apparatus'having a plurality of actuatingcoils for operating said controller in either direction, and a pluralityof relay devices connected across the respective armatures and severallyprovided with contact members that are connected in series-circuitrelation with one of said coils only when the voltage dierence of eachmachine from normal is less than a predetermined value.

l1. In a system of control, the combination with. a plurality ofdynamo-electric machines severally having armatures and field windings,of means for separately exciting said field windings, a controller forregulating such excitation, an apparatus having a plurality of actuatingcoils for operating said controller in either direction, and a pluralityof relay devices connected across the respective armatures and severallyprovided with contact members that are connected in series-circuitrelation with one of said coils only when the voltage difference of eachmachine from normal is less than a predetermined valuc, and anotherrelay device governed by the main-m achine current for opening andclosing the circuit of the other coil.

In testimony whereof l have hereunto subscribed my name this 31st day ofMay,

CHARLES C. VVHTTAKER.

